Method of manufacturing cap nuts



Patented Apr. 13, 1926.

UNITED STATES PATENT OFFICE.

WILLIAM R. WILEY, OF DETROIT, MICHIGAN, ASSIGNOR TO WISE ELECTRO SHERARD- IZING COMPANY, F DETROIT, MICHIGAN, A. CORPORATION OF MICHIGAN.

METHOD OF MANUFACTURING CAP NUTS.

applieaumi ined February s, 1922. serial No. 535,288. e

To all lwhom it may concern.:

Be it known that I, IVILL'IAM R. W'ILEY,

a citizen of the United States, residing at Detroit, county of Wayne, State of Michigan, have invented a certain new and Auseful Improvement in the Method of Manufacturing Cap Nuts, and declare the following tobe a full, clear, and exact description of the same, such as will enable others'skilled in the art to 'which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

This invention" relates to cap or acorn nuts, and a preferred process of manufacturing the same, and has for its object an improved article ,of this type, which can be made up from a centrally threaded body portion of cold-rolleds'teel, and a cap portion of stamped-out sheet metal, at a much less cost than is now involved in the production of unitary nuts' of this type as'now made entirely of cold-rolled steel, and subsequently machined to desired form at surprisin ly heavy expense. InY e drawings: v Figure l is an, elevation of the body of the nut.

Figure 2 shows the sheet metal cap in position` over the gnut and' before being slipped over the projecting grooved collar portion thereof.

Figure 3 shows the cap in place over the collar portion, and with the clinching die 1n initial position with respect thereto.

Figure 4 shows the die in the position attained`l at the end of its stroke, and with the cap in clinching position relatively to the collar.

Figure 5 is an elevation of the completed nut as thus assembled.

Figure 6 shows a die in position upon a cap which is adapted to be locked to its nut in a slightly modified manner.

Figure 7 is a. plan view from above of the type of construction illustrated in Figure 6.

Cap nutswhich are made entirely from cold-rolled steel bars now require several expensive machining steps to transform the cut-0E slugs of steel into the vcompleted hexagonal nut, with the centrally threaded bore extending up into the dome; andespeciall if the threading is at all carelessly done, it frequently happens that when a threaded bolt is inserted therein, the ti of the bolt cannot'be screwed far enoug into the cap, because not suicient material has been cut away from the interior of the dome, whose walls are of course needlessly thick, and correspondingly heavy. The greatest objection however, is the cost,- both in machining operations, and in waste material from the cut.

Cap nutsn havel been attempted along the lines of clinching or forcing a sheet metal thimble about the hexagonal sides of a nut, and, even with its edges bent under the lower edge of the nut in the attempt to clinch the cap tightly in place. vThis however isobjectionable, not only because of the tendency to loose fit of the nut within the cap, but also because of the tendency of a wrench, when ap lied to the completed hexagonal faces 0I the cap, to tear and crack the relatively thin sheet metal. l

To obviate this, I provide in the flrst instance a nut A, provided with the usual centrally threaded bore B, and with an upwardly projecting collar or neckjC, which is preferably cut or annularlygrooved, as at D. Over this I fit a cap or thimble piece E, which is of such internal diameter that it just slips over the edge of the collar C, andlso that its lower peripheral edge will rest upon the top or surrounding shoulder portion of the nut A. I then place this in a die press, whose forming member F is of very slightly less internal diameter than the external diameter of the cap E. When this is forced down, it pinches the cap or dome member inwardly slightly, thus forcing a. very slight shoulder or annular projection of metal against the upper edge of the collar C; this I have illustrated in, exaggerated proportion at G in Figure 4. The further downward travel of the formingdie continues the distortion of the metal of the cap, and as the line of pressure reaches the level of the groove B, some of the metal ows inwardly thereinto, as shown at I-I in Figure 4, while some of the rest tends to How slightly outward at the very edge, as shown at J, thus'eiecting a sealing between the cap and the body of the nut bolt as regards exterior appearance, and space of any consequential size therebetween. The inward projections G and H interlocking with the top of the collar C on each edge thereof. serve to hold the cap in place most elliciently, and the space within the dome of the cap is thus left of ample size for the threaded end of a bolt to project as far be. yond the end of the nut as could possibly be required. The stamping of these caps in place can be el'ected in very rapid succession, and the loading of the cap or thimble ieces upon a nut body can b e attended to y an inexperienced helper.

In Figures 6 and 7, I have illustrated a slightly modied form of construction, wherein, in place of the projecting neck C, an under-cut groove K is located in the body of the nut, the diameter and width thereof at the level of thetop of the nut being exactly that of lthe cap, which, when first ositioned therein, can reach only slight y beneath the top surface of the nut body. With the exertion of downward pressure u on the cap, due to the presence of the die the relatively soft sheet metal' of which the cap is composed is forced .to yield in the only direction which the contour of the groovemakes possible, that illustrated in Figures 6 and 7, being outwardly, though the same clinching elect would be secured if the inclination of the groove were inward. IVhen the stroke of the die has been completed, the cap is clinched in this form, the then position of the extreme peripheral edge being not only shown clearly in sectio'n in Figure 6, but indicated by 'dotted lines in Figure 7.

What I claim is:

The process of manufacturing a cap nut, consisting in fitting over the projecting end of a centrally threaded body portion a cupped sheet metal member of closely similar internal diameter, and subjecting the comlponent metal of the latter to the centripetal y deforming influence of an axially applied member of slightly lesser internal diameter than the initial external diameter' of said cupped member, thereby pressing the edges'of the latter into interlocking engagement with said projecting end oi the body portion.

In testimony whereof, I sign this specification.

WILLIAM R. 

